I tried to post a link but it didn't work. I typed in "Night of the Creeps" on ebay and there were several "Special editions with the tv version and the theatrical version", by folks with excellent ratings. I also typed in to Google and found movie sites that had DVD info.
Oh well. I got my hopes up but it's still not available on DVD. The discs you saw must have been bootlegs (for future reference links to bootlegs aren't allowed and will always be removed by an administrator).